Consequence Of Denaturation Research Articles

Resistant protein; its existence and function beneficial to health.

The remnants of proteins themselves or complexes with protein remaining no longer indigestible in the intestine are referred to as resistant proteins, which exert physiological functions similar to dietary fibers and are also better for health. In recent years, noticeable functions attributable to resistant proteins have become gradually apparent with regard to several proteinous items. Recent investigations have revealed that the relevant ingredients are either condensed in isolates or concentrates of vegetable proteins or causally brought about as a consequence of denaturation and/or entanglement in the process of preparation. Some protein components inherently insusceptible to mammalian digestive enzymes also belong to the group of resistant proteins in case of edibility irrespective of their sources. Among the medicinal benefits of several resistant proteins hitherto pointed out by animal experiments, there were preventive effects against hypercholesterolemia, constipation, corpulence, tumorigenesis (colon, liver, mammary gland), gallstone formation or poisoning, and wholesome improvements in enteric fermentation of short-chain fatty acids.

Determination and Derivatization of Protein Thiols by n-Octyldithionitrobenzoic Acid

n-Octyl-5-dithio-2-nitrobenzoic acid (ODNB), the reaction product of n-octane-1-thiol and Ellman′s reagent, can be isolated in crystalline form. Like Ellman′s reagent, ODNB can be used for the titration of SH groups in proteins, but with considerable advantages: Due to the absence of one negative charge and the presence of a lipophilic hydrocarbon chain, titrations of protein thiols are significantly faster. Normally, endpoints are reached after 5-30 min, while the corresponding reaction with Ellman′s reagent may take 1-2 h. Another advantage of ODNB is that it finds access to thiol groups which normally remain undetected. With myosin S1, for example, ODNB reacts with a thiol group which is not reactive with Ellman′s reagent. Although ODNB has detergent properties, reaction of this thiol group as a consequence of denaturation seems unlikely, because ODNB was used below its critical micelle concentration and all other thiols of myosin S1 remained buried. The n-octylthiol derivatives of proteins formed by reaction with ODNB can be used for transient protection of thiols, for example, during purification procedures, or for a reversible blocking of SH groups involved in biochemical reactions.